Recent scientific investigations have shown that many chemicals used in plastics, pharmaceuticals, pesticides, cosmetics, food additives, etc., are endocrine disrupting chemicals (EDCs). EDCs interfere in various ways with hormones, such as estrogens and androgens, and can have significant adverse effects on many behavioral and physiological processes. ED effects (agonistic or antagonistic) sometimes occur at very low (picomolar to nanomolar) concentrations, especially in fetal or developing mammals (including humans). The prevalence and actions of EDCs in our environment warrant the development of valid testing methods. Consequently, various governmental bodies (e.g., EPA, FDA, and ICCVAM) and proactive corporations have explicitly expressed a desire to have in vitro robotic assays for EDCs, such as for androgenic (AnA) or anti- androgenic (Anti-AnA) activity. However, no reliable manual or robotic AnA or Anti-AnA assays are yet commercially available. ICCVAM/NICEATM desire single laboratory validation assays of AnA and Anti-AnA using a human-based cell line. To begin to meet these governmental, scientific and commercial needs, CertiChem (CCi) is submitting a Fast-Track grant to show that it is feasible to develop AnA and Anti-AnA assays in manual and medium- throughput (robotic) formats that would be reliable, accurate, versatile, rapid, and cost effective. CCi proposes to use MDA-kb2 human-based cells. In our AnA and anti-AnA assays, these cells will be examined by a transcription reporter gene (luciferase) assay. CCi proposes to examine 77 Test Substances supplied and coded by ICCVAM for AnA and Anti-AnA validation to confirm that CCi's assays can accurately assess their AR agonistic and antagonistic activities. CCi also proposes to test hydrophilic and hydrophobic extracts of 30 silicone and paper products for AnA and Anti-AnA. Development of manual and robotic screening assays for AnA and anti-AnA is highly desired as part of the mission of NIEHS, EPA, and ICCVAM as commercially, scientificly, and socially important. Government agencies are now screening a large number of chemicals for hormonal activity, including AR agonist and antagonist activities. In addition, hormonal activity of chemical mixtures extracted from commercial products is of great importance to government agencies, NGOs, and consumers.